surface/aggregator/ssh_packet_layer.c

42  * - transmission start (process next item in queue)
53  * The code below employs two main data structures: The packet queue,
60  * - the packet queue,
68  * packets from the queue. By doing this, it does not increment the refcount
69  * but takes over the reference (removing it from the queue). If the packet is
99  * packet cannot be added to the queue, the pending set, and the timeout, or
102  * references from the data structures (queue, pending) have to be removed.
135  *   Indicates if a packet is present in the submission queue or not. This flag
136  *   must only be modified with the queue lock held, and must be coherent to the
137  *   presence of the packet in the queue.
167  * - To avoid deadlocks, if both queue and pending locks are required, the
168  *   pending lock must be acquired before the queue lock.
170  * - The packet priority must be accessed only while holding the queue lock.
680 /* Must be called with queue lock held. */
686 	lockdep_assert_held(&p->ptl->queue.lock);
691 	 * is guarded by the queue lock, so no need to use READ_ONCE() there.
696 /* Must be called with queue lock held. */
702 	lockdep_assert_held(&p->ptl->queue.lock);
713 	 * are, usually queued directly at the tail of the queue, so for those
718 		list_for_each(head, &p->ptl->queue.head) {
725 		list_for_each_prev(head, &p->ptl->queue.head) {
738 /* Must be called with queue lock held. */
744 	lockdep_assert_held(&ptl->queue.lock);
767 	spin_lock(&packet->ptl->queue.lock);
769 	spin_unlock(&packet->ptl->queue.lock);
778 	spin_lock(&ptl->queue.lock);
781 		spin_unlock(&ptl->queue.lock);
787 	spin_unlock(&ptl->queue.lock);
907 	spin_lock(&ptl->queue.lock);
908 	list_for_each_entry_safe(p, n, &ptl->queue.head, queue_node) {
911 		 * It's going to be removed from this queue shortly.
928 		 * queue and mark it as being transmitted.
943 		 * queue lock.
950 	spin_unlock(&ptl->queue.lock);
1361  * on the queue, and %-ESHUTDOWN if the transmission layer has been shut down.
1372 	spin_lock(&packet->ptl->queue.lock);
1377 		spin_unlock(&packet->ptl->queue.lock);
1388 		spin_unlock(&packet->ptl->queue.lock);
1394 	spin_unlock(&packet->ptl->queue.lock);
1409 	 * ssh_ptl_tx_next() removed the packet from the queue and updated the
1416 	/* Re-queue all pending packets. */
1468 	 * the packet cannot be added to the queue any more.
1474 	 * the packet will never be added to the queue. If packet->ptl is
1948 	 * only references to packets from inside the system are in the queue
1955 	 * packet as locked an then remove it from the queue (or pending set
1967 	spin_lock(&ptl->queue.lock);
1968 	list_for_each_entry_safe(p, n, &ptl->queue.head, queue_node) {
1976 	spin_unlock(&ptl->queue.lock);
2034 	spin_lock_init(&ptl->queue.lock);
2035 	INIT_LIST_HEAD(&ptl->queue.head);